summaryrefslogtreecommitdiffstats
path: root/src/vnet/tcp/tcp_input.c
diff options
context:
space:
mode:
authorFlorin Coras <fcoras@cisco.com>2019-03-12 18:58:54 -0700
committerDamjan Marion <dmarion@me.com>2019-03-22 17:30:29 +0000
commit4759683744d079f868a6bcca8084eba8466620d7 (patch)
tree6795035edf69463107dfbaa54eae3183cdc62356 /src/vnet/tcp/tcp_input.c
parent881d13ede7336e5b16601033e5dd9aeb94c795e3 (diff)
tcp: improve handling of snd_nxt
- avoid changing snd_nxt when doing fast retransmits - use snd_una_max only to keep track of the max seq number sent - simplify future ack testing Change-Id: I3580ad3aefe30128486c3375d0ac3f3f62c04c5e Signed-off-by: Florin Coras <fcoras@cisco.com>
Diffstat (limited to 'src/vnet/tcp/tcp_input.c')
-rw-r--r--src/vnet/tcp/tcp_input.c112
1 files changed, 49 insertions, 63 deletions
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 5235c20a565..c27631f3965 100644
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -409,7 +409,7 @@ tcp_rcv_ack_is_acceptable (tcp_connection_t * tc0, vlib_buffer_t * tb0)
{
/* SND.UNA =< SEG.ACK =< SND.NXT */
return (seq_leq (tc0->snd_una, vnet_buffer (tb0)->tcp.ack_number)
- && seq_leq (vnet_buffer (tb0)->tcp.ack_number, tc0->snd_nxt));
+ && seq_leq (vnet_buffer (tb0)->tcp.ack_number, tc0->snd_una_max));
}
/**
@@ -604,7 +604,7 @@ tcp_ack_is_dupack (tcp_connection_t * tc, vlib_buffer_t * b, u32 prev_snd_wnd,
u32 prev_snd_una)
{
return ((vnet_buffer (b)->tcp.ack_number == prev_snd_una)
- && seq_gt (tc->snd_una_max, tc->snd_una)
+ && seq_gt (tc->snd_nxt, tc->snd_una)
&& (vnet_buffer (b)->tcp.seq_end == vnet_buffer (b)->tcp.seq_number)
&& (prev_snd_wnd == tc->snd_wnd));
}
@@ -913,7 +913,7 @@ tcp_scoreboard_is_sane_post_recovery (tcp_connection_t * tc)
sack_scoreboard_hole_t *hole;
hole = scoreboard_first_hole (&tc->sack_sb);
return (!hole || (seq_geq (hole->start, tc->snd_una)
- && seq_lt (hole->end, tc->snd_una_max)));
+ && seq_lt (hole->end, tc->snd_nxt)));
}
#ifndef CLIB_MARCH_VARIANT
@@ -943,8 +943,8 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
if (seq_lt (blk->start, blk->end)
&& seq_gt (blk->start, tc->snd_una)
&& seq_gt (blk->start, ack)
- && seq_lt (blk->start, tc->snd_una_max)
- && seq_leq (blk->end, tc->snd_una_max))
+ && seq_lt (blk->start, tc->snd_nxt)
+ && seq_leq (blk->end, tc->snd_nxt))
{
blk++;
continue;
@@ -979,7 +979,7 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
{
/* If no holes, insert the first that covers all outstanding bytes */
last_hole = scoreboard_insert_hole (sb, TCP_INVALID_SACK_HOLE_INDEX,
- tc->snd_una, tc->snd_una_max);
+ tc->snd_una, tc->snd_nxt);
sb->tail = scoreboard_hole_index (sb, last_hole);
tmp = tc->rcv_opts.sacks[vec_len (tc->rcv_opts.sacks) - 1];
sb->high_sacked = tmp.end;
@@ -990,17 +990,17 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
* last hole end */
tmp = tc->rcv_opts.sacks[vec_len (tc->rcv_opts.sacks) - 1];
last_hole = scoreboard_last_hole (sb);
- if (seq_gt (tc->snd_una_max, last_hole->end))
+ if (seq_gt (tc->snd_nxt, last_hole->end))
{
if (seq_geq (last_hole->start, sb->high_sacked))
{
- last_hole->end = tc->snd_una_max;
+ last_hole->end = tc->snd_nxt;
}
/* New hole after high sacked block */
- else if (seq_lt (sb->high_sacked, tc->snd_una_max))
+ else if (seq_lt (sb->high_sacked, tc->snd_nxt))
{
scoreboard_insert_hole (sb, sb->tail, sb->high_sacked,
- tc->snd_una_max);
+ tc->snd_nxt);
}
}
/* Keep track of max byte sacked for when the last hole
@@ -1078,8 +1078,7 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
if (pool_elts (sb->holes) == 1)
{
hole = scoreboard_first_hole (sb);
- if (hole->start == ack + sb->snd_una_adv
- && hole->end == tc->snd_una_max)
+ if (hole->start == ack + sb->snd_una_adv && hole->end == tc->snd_nxt)
scoreboard_remove_hole (sb, hole);
}
@@ -1088,8 +1087,8 @@ tcp_rcv_sacks (tcp_connection_t * tc, u32 ack)
- (old_sacked_bytes - sb->last_bytes_delivered);
ASSERT (sb->last_sacked_bytes <= sb->sacked_bytes || tcp_in_recovery (tc));
ASSERT (sb->sacked_bytes == 0 || tcp_in_recovery (tc)
- || sb->sacked_bytes < tc->snd_una_max - seq_max (tc->snd_una, ack));
- ASSERT (sb->last_sacked_bytes + sb->lost_bytes <= tc->snd_una_max
+ || sb->sacked_bytes < tc->snd_nxt - seq_max (tc->snd_una, ack));
+ ASSERT (sb->last_sacked_bytes + sb->lost_bytes <= tc->snd_nxt
- seq_max (tc->snd_una, ack) || tcp_in_recovery (tc));
ASSERT (sb->head == TCP_INVALID_SACK_HOLE_INDEX || tcp_in_recovery (tc)
|| sb->holes[sb->head].start == ack + sb->snd_una_adv);
@@ -1146,7 +1145,7 @@ void
tcp_cc_init_congestion (tcp_connection_t * tc)
{
tcp_fastrecovery_on (tc);
- tc->snd_congestion = tc->snd_una_max;
+ tc->snd_congestion = tc->snd_nxt;
tc->cwnd_acc_bytes = 0;
tc->snd_rxt_bytes = 0;
tc->prev_ssthresh = tc->ssthresh;
@@ -1162,7 +1161,6 @@ tcp_cc_recovery_exit (tcp_connection_t * tc)
tc->rto_boff = 0;
tcp_update_rto (tc);
tc->snd_rxt_ts = 0;
- tc->snd_nxt = tc->snd_una_max;
tc->rtt_ts = 0;
tcp_recovery_off (tc);
TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 3);
@@ -1175,7 +1173,6 @@ tcp_cc_fastrecovery_exit (tcp_connection_t * tc)
tc->cc_algo->recovered (tc);
tc->snd_rxt_bytes = 0;
tc->rcv_dupacks = 0;
- tc->snd_nxt = tc->snd_una_max;
tc->snd_rxt_bytes = 0;
tc->rtt_ts = 0;
@@ -1191,12 +1188,16 @@ tcp_cc_congestion_undo (tcp_connection_t * tc)
{
tc->cwnd = tc->prev_cwnd;
tc->ssthresh = tc->prev_ssthresh;
- tc->snd_nxt = tc->snd_una_max;
tc->rcv_dupacks = 0;
if (tcp_in_recovery (tc))
- tcp_cc_recovery_exit (tc);
+ {
+ tcp_cc_recovery_exit (tc);
+ tc->snd_nxt = seq_max (tc->snd_nxt, tc->snd_congestion);
+ }
else if (tcp_in_fastrecovery (tc))
- tcp_cc_fastrecovery_exit (tc);
+ {
+ tcp_cc_fastrecovery_exit (tc);
+ }
ASSERT (tc->rto_boff == 0);
TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 5);
}
@@ -1374,8 +1375,7 @@ tcp_cc_handle_event (tcp_connection_t * tc, u32 is_dack)
else if (is_dack && !tcp_in_recovery (tc))
{
TCP_EVT_DBG (TCP_EVT_DUPACK_RCVD, tc, 1);
- ASSERT (tc->snd_una != tc->snd_una_max
- || tc->sack_sb.last_sacked_bytes);
+ ASSERT (tc->snd_una != tc->snd_nxt || tc->sack_sb.last_sacked_bytes);
tc->rcv_dupacks++;
@@ -1482,8 +1482,6 @@ partial_ack:
return;
}
- tc->snd_nxt = tc->snd_una_max;
-
/* Treat as congestion avoidance ack */
tcp_cc_rcv_ack (tc);
return;
@@ -1565,38 +1563,18 @@ tcp_rcv_ack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc, vlib_buffer_t * b,
/* If the ACK acks something not yet sent (SEG.ACK > SND.NXT) */
if (PREDICT_FALSE (seq_gt (vnet_buffer (b)->tcp.ack_number, tc->snd_nxt)))
{
- /* When we entered cong recovery, we reset snd_nxt to snd_una. Seems
- * peer still has the data so accept the ack */
- if (tcp_in_cong_recovery (tc)
- && seq_leq (vnet_buffer (b)->tcp.ack_number,
- tc->snd_una + tc->snd_wnd))
+ /* We've probably entered recovery and the peer still has some
+ * of the data we've sent. Update snd_nxt and accept the ack */
+ if (seq_leq (vnet_buffer (b)->tcp.ack_number, tc->snd_una_max))
{
tc->snd_nxt = vnet_buffer (b)->tcp.ack_number;
- if (seq_gt (tc->snd_nxt, tc->snd_una_max))
- tc->snd_una_max = tc->snd_nxt;
goto process_ack;
}
- /* If we have outstanding data and this is within the window, accept it,
- * probably retransmit has timed out. Otherwise ACK segment and then
- * drop it */
- if (seq_gt (vnet_buffer (b)->tcp.ack_number, tc->snd_una_max))
- {
- tcp_program_ack (wrk, tc);
- *error = TCP_ERROR_ACK_FUTURE;
- TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 0,
- vnet_buffer (b)->tcp.ack_number);
- return -1;
- }
-
- TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 2,
+ *error = TCP_ERROR_ACK_FUTURE;
+ TCP_EVT_DBG (TCP_EVT_ACK_RCV_ERR, tc, 0,
vnet_buffer (b)->tcp.ack_number);
-
- tc->snd_nxt = vnet_buffer (b)->tcp.ack_number;
- if (seq_gt (tc->snd_nxt, tc->snd_una_max))
- tc->snd_una_max = tc->snd_nxt;
-
- goto process_ack;
+ return -1;
}
/* If old ACK, probably it's an old dupack */
@@ -1611,10 +1589,11 @@ tcp_rcv_ack (tcp_worker_ctx_t * wrk, tcp_connection_t * tc, vlib_buffer_t * b,
return 0;
}
+process_ack:
+
/*
* Looks okay, process feedback
*/
-process_ack:
if (tcp_opts_sack_permitted (&tc->rcv_opts))
tcp_rcv_sacks (tc, vnet_buffer (b)->tcp.ack_number);
@@ -1767,13 +1746,7 @@ tcp_update_sack_list (tcp_connection_t * tc, u32 start, u32 end)
/* Save to new SACK list if we have space. */
if (vec_len (new_list) < TCP_MAX_SACK_BLOCKS)
- {
- vec_add1 (new_list, tc->snd_sacks[i]);
- }
- else
- {
- clib_warning ("sack discarded");
- }
+ vec_add1 (new_list, tc->snd_sacks[i]);
}
ASSERT (vec_len (new_list) <= TCP_MAX_SACK_BLOCKS);
@@ -2799,7 +2772,7 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
tcp_send_fin (tc0);
}
/* If FIN is ACKed */
- else if (tc0->snd_una == tc0->snd_una_max)
+ else if (tc0->snd_una == tc0->snd_nxt)
{
tcp_connection_set_state (tc0, TCP_STATE_FIN_WAIT_2);
@@ -2845,8 +2818,21 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
/* In addition to the processing for the ESTABLISHED state, if
* the ACK acknowledges our FIN then enter the TIME-WAIT state,
* otherwise ignore the segment. */
- if (tcp_rcv_ack (wrk, tc0, b0, tcp0, &error0))
- goto drop;
+ if (!tcp_rcv_ack_is_acceptable (tc0, b0))
+ {
+ error0 = TCP_ERROR_ACK_INVALID;
+ goto drop;
+ }
+
+ error0 = TCP_ERROR_ACK_OK;
+ tc0->snd_una = vnet_buffer (b0)->tcp.ack_number;
+ /* Ack moved snd_una beyond snd_nxt so reprogram fin */
+ if (seq_gt (tc0->snd_una, tc0->snd_nxt))
+ {
+ tc0->snd_nxt = tc0->snd_una;
+ tc0->flags &= ~TCP_CONN_FINSNT;
+ goto drop;
+ }
tcp_connection_timers_reset (tc0);
tcp_connection_set_state (tc0, TCP_STATE_TIME_WAIT);
@@ -2867,7 +2853,7 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
error0 = TCP_ERROR_ACK_OK;
tc0->snd_una = vnet_buffer (b0)->tcp.ack_number;
/* Apparently our ACK for the peer's FIN was lost */
- if (is_fin0 && tc0->snd_una != tc0->snd_una_max)
+ if (is_fin0 && tc0->snd_una != tc0->snd_nxt)
{
tcp_send_fin (tc0);
goto drop;
@@ -2971,7 +2957,7 @@ tcp46_rcv_process_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
tcp_fastrecovery_off (tc0);
tcp_recovery_off (tc0);
tcp_connection_timers_reset (tc0);
- tc0->snd_nxt = tc0->snd_una_max = tc0->snd_una;
+ tc0->snd_nxt = tc0->snd_una;
}
tcp_send_fin (tc0);
}